What is the souce of most iron supplements? I have heard rumors of some yucky places that iron supplents (pills) may come from.
Metallic iron is virtually unknown on the surface of the Earth except as iron-nickel alloys from meteorites and very rare forms of deep mantle xenoliths. Therefore, all sources of iron used by human industry exploit iron oxide minerals, the primary form which is used in industry being hematite. However in some situations, more inferior iron ore sources have been used by industrialized societies when access to high-grade hematite ore was not available. This has included utilisation of taconite in the United States, after World War II, and goethite or bog ore used during the American Revolution and the Napoleonic wars. Magnetite is often used because it is magnetic and hence easily liberated from the gangue minerals. Inferior sources of iron ore generally require beneficiation. Due to the high density of hematite relative to silicates, beneficiation usually involves a combination of crushing and milling as well as heavy liquid separation. This is achieved by passing the finely crushed ore over a bath of solution containing bentonite or other agent which increases the density of the solution. When the density of the solution is properly calibrated, the hematite will sink and the silicate mineral fragments will float and can be removed. Iron ore mining methods vary by the type of ore being mined. There are four main types of iron ore deposits worked currently, depending on the mineralogy and geology of the ore deposits. These are magnetite, titanomagnetite, massive hematite and pisolitic ironstone deposits.
